Mechanical coal stoker



Sept. 29, 1936. R. JOHNSON 2,055,725

MECHANICAL COAL STOKER Filed Sept. 13, 1935 A 3| I 32 a 46 Fig.4

Roy Johnson Patented Sept. 29,

UNITED STAT es PATENT OFFICE 7 Claims.

My invention relates to coal feeding devices, and is more particularly designed as a feeding device for domestic stokerausing granular coal.

Amongthe objects of my invention are: to proside of the outer end of the feed opening ill, the core tapers downward from a maximum diameter at this point to a. minimum diameter at or near the inner end of the feed opening ID. This tavide a domestic stoker which maybe cheaply y manufactured; which is provided with means tb automatically prevent clogging and to vary the rate of iced of the coal as desired; which can be readily dismounted and the feed screw removed to pered portion is indicated at 24!. Means, to be later described, are provided for rotating the feed screw in a direction to advance the coal in the pipe toward the inner end.

break a jam or to clear away any clogging, even though the hopper may be filled, and without the necessity of empmg the hopper; andwhich is simple throughout and convenient to assemble and to adjust.

My invention comprisesthe novel parts, and the novel assembly and arrangement of these parts relative to each other, as'shown in the accompanying drawing, and as will be described in this specification and more particularly pointed out by the claims which terminate the same.

In the accompanyingvdrawing I have shown my invention embodied in a stokerofthe type and design new preferred by me, it beingunderstood, however, that various changes may be made the form, proportions, and arrangemerit oi parts without departing from-the spirit of my invention as defined by the claims.

Figure i is aside elevation of'the feed arrangement, the parts being broken away and shown in section.

Cooperating with the feed opening Hi and the tapered portion 2! of the feed screw is a gate 3. Preferably this is a piece of metal of a shape to fit the outside of the pipe I, and rests and slides .upon this pipe.

in proper alignment. The inner wall of the hopper throat I2 is slotted; closely adjacent its junction with the pipe 3, as is best seen in Figure 2, for the projection of the gate 3 over the feed opening ill, and the gate 3 is adjustable from the innerend of the feed opening it toward the latters outer end. Such adjustment is conveniently accomplished by an adjusting screw 36 swdveled in a lug 3i secured upon the pipe, and threadedly 3 received in a lug32 carriedby the gate 3. The screwxmaybe rotated by a handle 33, slidably "purposely is placed closely adjacent the pipe E received in the end of the screw, which handle so that it may not be casually adjusted, but yet canbe adjusted when required. Preferably also,

Figure 2 m a similar elevation fromthe opposite v side, the gear box and feed screw being removed,

- and parts being shown in section. =1

' Figure 3 is a sectional view through the gear hDEyEhQWlHE it associated with thefeed screw,

and this view complements Figure 2.

Figure 4: is an elevation of the feed device, with ,inl igure 2, which reinforces the end of the gate, and which, being of a shape and curvature sub- ,stantially coinciding with the inside of the pipe, insures that any coal passing between it and the the motor and all associated parts removed-and with the hopper throat shown in section.

- Figure :5 is a transverse section through the gear hos, substantially on the line 5-45 of Figureil. ,7 i

p The iced inc '3 is or may be an Ord nary pipe, preferably of uniform diameter throughout. Coal is advanced iromlts outer end toward itsinner end for delivery to a suitable burner (not shown) in a direction indicated by the arrow A. Inside 01! its outer end it is provided with a feed opening I. in its upper side, and a hopper I I provided with or throat l2 ismounted directly on the pipe I in regis y with the feed opening Ill. i i A feed screw 2 is received in the pipe I, being insertable through its outerend- This feed screw -.is provided. with ahelical thread 20, which is M gear box I; havinga shaft ll! coupled by removafeed screw is not greater in volume than the capacity of the pipe, hence will not jam: nor clog the pipe.

1 It will now become apparent that the gate 3 maybe adjusted lengthwise of the feed opening ,in-cooperation with the tapered portion 2i of the feed screw, and that by such adjustment, not only. is the effective area of the feed opening adjusted, but also the effective depth of the valley of the feed screw is adjusted, and that the feed -screw in substantially all adjusted positions of ,the gate will have increased depth inwardly or I the edge of the gate, so that any mass of coal ,,which will pass beneath the edge of the gate 3 will clear itself beyond that point, and no piece 1 larger than the space between the cylindrical core of the feed screw and the pipe can pass into the pipe.v Thus it is automatically insured that there will be no clogging in the inner end of the pipe,

approximately of a sizeitoflll the inside diameter or between the pipe and the feed screw.

The feed screw is conveniently driven from a 'ble coupling means :41 to the outer end of the feed Guides 35 support it and hold it screw, the gear box also having a sleeve which 'is' telescopically received in the outer end of the pipe 2. It may be supported therein by means uch as the set screw 43 (seeFigure'l), and this permits the belt 44, connecting the drive wheel 45 on shaft 46 of the gear box and the drive pulley 55 of a motor mounted on the pipe, to be tightened as desired.

The motor 5 is mounted in a bracket 50 which is secured directly upon the outer end of the pipe I, and the motor may be of a type which incorporates a resilient mounting between itself and the bracket 50. The belt drive permits ready disengagement of the gear box from the motor, and upon removal of 'the set screw 43, the gear box may be removed, drawing with it the feed screw 2. If the hopper is filled, communication between the hopper and the pipe may be cut 013? by closing the gate 3, hence the only coal which needs to be removed is that which is within the pipe i.

It is desirable to employ an air draft with such stokers, and to that end I may mount a fan housing 6 upon the bracket 50, or otherwise upon the outer end of the pipe I, in alignment with the motor, the fan 66 within the housing 6 being directly coupled to the motor shaft. An air feed conduit 60 leads to the burner (not shown) The fan housing is provided with an inlet opening 6| in one side, and a plate 62 having a bolt 63 threa-dedly received in the fan housing 6 may be adjusted inwardly or outwardly of the fan housing to vary the eifective area of the air inlet opening, thus constituting a simple, yet effective, means of adjusting the amount of air delivered.

What I claim as my invention is:

1. A device for feeding granular coal to stokers, comprising a pipe of uniform diameter, having a feed opening in its side, means delivering coal through such feed opening to the pipe, and a feed screw disposed in said pipe and extending lengthwise beneath and beyond the feed opening, said screw having a helical thread and a central core tapering from a maximum at one side of such opening to a lesser size at the otherside thereof, and rotatable in a direction to advance coal in the direction of the lesser size of said core, and a gate disposed substantially in the periphery of the pipe, and movable relative to the feed opening to vary the effective depth of thread on the tapered core, exposed to coal delivered through the feed opening.

2. A device for feeding granular coal to stokers, comprising a pipe of uniform diameter, having a feed opening in its side, means delivering coal through such feed opening to the pipe, a feed screw disposed in said pipe and extending lengthwise beneath and beyond the feed opening, said screw having a helical thread and a central core tapering from a maximum at one side of such opening to a lesser size at the other side thereof, and rotatable in a direction to advance coal in the direction of the lesser size of said core, and means movable from the latter end of the feed opening, lengthwise of the latter, to vary its effective size, and cooperating with the tapered core to restrict the eifective volume of coal delivered into and through the pipe. 7

' 3. A device for feeding granular coal to stokers, comprising a pipe of uniform diameter adapted for advance of coal from its outer end towards its inner end, and having a feed opening in its upper side, a hopper thereabove delivering coal through such opening into the pipe, a feed screwdisposed in said pipe and having a helical thread of approximately the inside diameter of the pipe, the

central core of said feed screw being tapered from a minimum diameter, inside the pipe from the feed opening, to a greater diameter beyond the outer end of the feed opening, and a gate having an edge disposed in the feed opening and coin-' ciding in size and curvature to the inside diameter of the pipe, said gate being slidabl'e lengthwise of the pipe from the inner end of the feed opening, such edge cooperating with the edges of the feed opening to vary the effective size of the latter, and cooperating with the tapered core to vary the effective depth of the valley of the feed screw immediately beneath the feed opening.

4. A coal feeding device for stokers, comprising a pipe of uniform diameter adapted for advance of coal from its outer end towards its inner end, and having a feed opening in its upper side, a hopper thereabove delivering coal through such opening into the pipe, said hopper, closely adjacent the inner end of the, feed opening, being slotted, a gate of curvatureconformingto, and slidably mounted on, the pipe, and projecting through said slot, means to adjust the spacing between the c iter end of said gate and the inner end of the feed opening, to vary the effective length of such opening, a feed screw having a helical thread of approximately the inside diameter of the pipe, and a central core tapering down, beneath the feed opening, from a maximum at the outer end of the latter to a minimum at its inner end, said gate cooperating with said tapered core to vary the effective depth of the valley of the feed screw immediately beneath the feed opening, and means to rotate said feed screw in a direction to advance the coal towards the inner end of said pipe.

5. A coal feeding device for stokers, comprising a feed pipe, a hopper delivering coal thereinto, a feed screw in the pipe rotatable to ad'- vance coal towards its inner end, drive means for said feed screw including a motor mounted on the feed pipe, 9, gear box having a sleeve receivable in the outerend of the pipe, a shaft in the gear box aligned with the feed screw, a coupling connecting the shaft and feed screw, a belt connecting the motor and gear box, and releasable means to retain the sleeve engaged in the pipe inany desired position, whereby the belt may be tightened at will.

61 A coal feeding device for stokers, comprising a feed pipe, a hopper delivering coal thereinto, a feed screw in the pipe rotatable to advance coal towards its inner end, drive means for said feed screw including a motor directly mounted on the outer end of the pipe, a gear box having a sleeve telescopically received in the outer end of the pipe and operatively connected to the feed screw, and a belt connecting the motor and gear box.

7. A coal feeding device for stokers, comprising a feed pipe, a hopper delivering coal thereinto,'a feed screw in the pipe rotatable to advance coal towards its inner end, drive means for said feed 

